Orthodontic treatment involves movement of malpositioned teeth to orthodontically correct positions. Tiny orthodontic appliances known as brackets are connected to exterior surfaces of the patient's teeth, and an archwire is placed in a slot of each bracket. The archwire forms a track to guide movement of the teeth to desired positions for correct occlusion. End sections of the archwire are often received in appliances known as buccal tubes that are fixed to the patient's molar teeth. In recent years it has become common practice to bond orthodontic appliances directly to the surface of the tooth.
For many years, it was common practice to apply orthodontic adhesive to the base of directly-bonded appliances immediately before the appliances were placed on the tooth. In some instances, a quantity of adhesive was dispensed onto a mixing pad or dispensing well and a small spatula or other hand instrument was then used to apply a small dab of adhesive to each appliance. In other instances, a quantity of adhesive was dispensed from a syringe directly onto the base of the appliance.
Adhesive precoated brackets are known and offer significant advantages to the orthodontist. Adhesive precoated brackets have a bonding base upon which the manufacturer may apply a precise quantity of adhesive such as a photocurable adhesive. When it is desired to mount the bracket on a tooth, the bracket is simply removed from the package and placed directly onto the tooth surface.
Adhesives used on precoated brackets are, in general, more viscous (i.e., less fluid) than other available orthodontic bonding adhesives. The higher viscosity ensures that the adhesive retains its shape and does not separate or distort when the bracket is lifted from the package for use. However, some orthodontists prefer the use of less viscous (i.e., more fluid) adhesives in order to facilitate manipulation of the bracket before the adhesive is cured. For example, brackets with less viscous adhesives are relatively easy to slide along the tooth surface when an effort is made to align the bracket in a proper, precise orientation on the tooth before the adhesive is cured.
Some practitioners prefer two-part chemical-cure adhesives (such as UNITE brand adhesive, from 3M Unitek Corporation) over light-curable adhesives. Orthodontic brackets precoated with one part of a two-part adhesive on the base of the bracket have been reported. After the bracket is removed from the package, a second part is applied to the bracket base and/or the tooth surface, and the bracket is then applied to the surface of the patient's tooth. Reported packages for brackets precoated with one part of a two-part chemical-cure adhesive include, referring to FIG. 1, an assembly 10 having a carrier 12 with arms 14 and 15 to suspend the bracket 16 with adhesive 22 in the container 18, and, referring to FIG. 2, an assembly 10 with container 18 having an uneven, dimpled, or “V” shaped reservoir 19 in contact with the adhesive 22 on bracket 16. Presently, there is a need in the art for improved configurations for delivering brackets precoated with chemical-cure adhesives to the practitioner.